(C #)?? Operator

Private icacheclient _cache;public icacheclient cache{    get    {         ?? (_cache = hostcontext.resolve<icacheclient> ());}    }

　There is one in this code?? operator, I have always thought that this operator is (?:) A variant of the conditional operator that today only understands its true meaning.

?? operator is called a null merge operator. If the left operand of this operator is not NULL, this operator returns the operand, otherwise the right operand is returned.

Then the meaning of the above program is: If _cache is not NULL, then return--cache; otherwise assign the value of hostcontext.resolve<icacheclient> () to it and return it.

(C #)?? Operator